Suffering from progressive deafness, Dr. Kirk Langstrom developed a serum derived from a gland found in bats
to give himself a natural sonar. Although successful the serum had a drawback, he was transformed into a bat-like
creature and became increasingly insane.

Due to the insanity which gripped him, Langstrom battled the Batman, but with the Dark Knight's assistance he
was able to eventually control his transformations and the madness of the Man-Bat.